1. Field of the Invention
The invention which relates to linear displacement sampling valves, particularly for the transfer of blood samples, relates more precisely to the structure of the valve and its fixing means facilitating assembly and disassembly thereof while providing a more efficient sealing.
2. Description of the Prior Art
This type of linear displacement valve is well known, formed essentially of a central mobile element sandwiched between two fixed external elements. Said central element is provided with at least one transverse passage orifice and moves in translation from a first fixed position to a second fixed position, in each of which positions the orifice in question is aligned with one or two opposite orifices provided on the external elements for connecting two ducts together or for dividing a sample volume into segments and transferring it to another path. The central element slides between the two fixed elements under the action of an actuator rod with spring return. This type of valve lends itself particularly well to the transfer of liquids such as blood, but the ducts and the orifices must always be correctly drained and cleaned so that sampling takes place under the best conditions of operation and cleanliness. Although precise manufacturing tolerances may have been respected, and although the sealing is correct, it is always indispensable, in valves of this type, to be able to have access frequently to the main parts, namely the central mobile element and the external elements, for cleaning them, cleaning out the orifices, adjusting or improving the displacement travel of the sliding part etc..
In conventional valves, these dismantling operations are time-consuming and fastidious for they involve the unscrewing of several parts, the disconnection of the inlet and outlet ducts and the removal of protecting members, before being able to release the central parts.
Thus, for simplifying these assembly-disassembly operations at the same time as reducing the parts forming the valve, and so as to obtain an assembly of reduced size and to improve the operation thereof, the invention provides a valve and a device for fixing its elements which then avoids the drawbacks experienced with linear displacement valves of known type.